The majority of oil and gas exploration is carried out in seas at a depth of 1000 meters. Due to the gradual increase in demand for energy, offshore oil and gas exploration has been moving into deeper waters, such as seabeds at depths of 3000 meters. In order to secure effective and safe production, power electronic converters are installed under the sea and need to withstand the high pressure environment at the seabed.
A common method used in current offshore gas and oil exploration is to install the power electronic converters in a container able to withstand water pressure at a certain sea depth. However, as the rated power of power electronic converters in the depths of the sea increases, the thickness of the wall of the above-mentioned container needs to increase in order to withstand the increased water pressures at the seabed, leading to enormous increases in the volume and weight of the container, making it difficult to install such a container on the seabed. The above-mentioned increase of water pressure at the seabed due to increased depth can cause semiconductor chips in power electronic converters to be damaged by the pressure.
Furthermore, in order to isolate the power electronic converters from the undersea environment, the above-mentioned containers need to be sealed, and in one example, sealing of the container can be achieved using sealant. However, the continuing increases of sea depth leads to continual increases in the external pressure sustained by the container, further leading to increases in the pressure differential between the inside and outside of the container. This increase in pressure differential can easily damage the sealant used to seal the container, increasing the difficulty in sealing the container.